| As automation and control systems in manufacturing, transportation, telecommunications, and other applications become more complex, designers realize the need to move away from using specialized, custom hardware and software to using the latest Commercial-Off-The-Shelf (COTS) hardware and software resources to the greatest extent possible to increase designer productivity and reduce costs. Unfortunately, the move to the use of COTS hardware and software makes it more difficult for the designers to ensure the safety of the systems when these systems are used in safety-critical applications.; To address this dilemma, a technique for designing safety-critical systems known as Algorithm-Based Safety Assurance (ABSA) is developed and described in this dissertation. ABSA ensures that the algorithm that defines the application is executed correctly (with a certain probability), rather than ensuring the correct operation of the hardware/software implementation. As such, the safety is ensured independent of the actual implementation, and thus ABSA supports the use of COTS hardware and software when designing safety-critical systems. Specific contributions presented in this dissertation are: (1) the definition and development of ABSA which ensures the correct execution of a Data Processing Algorithm (DPA) using a Check Processing Algorithm (CPA) to verify that properties associated with the DPA are correct, (2) the development of an encoding technique that supports ABSA, and (3) the development of an architectural-level design of an example application that uses ABSA to implement a fail-safe digital filter. |
